xref: /linux/include/net/nexthop.h (revision 9410645520e9b820069761f3450ef6661418e279)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Generic nexthop implementation
4  *
5  * Copyright (c) 2017-19 Cumulus Networks
6  * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
7  */
8 
9 #ifndef __LINUX_NEXTHOP_H
10 #define __LINUX_NEXTHOP_H
11 
12 #include <linux/netdevice.h>
13 #include <linux/notifier.h>
14 #include <linux/route.h>
15 #include <linux/types.h>
16 #include <net/ip_fib.h>
17 #include <net/ip6_fib.h>
18 #include <net/netlink.h>
19 
20 #define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK
21 
22 struct nexthop;
23 
24 struct nh_config {
25 	u32		nh_id;
26 
27 	u8		nh_family;
28 	u8		nh_protocol;
29 	u8		nh_blackhole;
30 	u8		nh_fdb;
31 	u32		nh_flags;
32 
33 	int		nh_ifindex;
34 	struct net_device *dev;
35 
36 	union {
37 		__be32		ipv4;
38 		struct in6_addr	ipv6;
39 	} gw;
40 
41 	struct nlattr	*nh_grp;
42 	u16		nh_grp_type;
43 	u16		nh_grp_res_num_buckets;
44 	unsigned long	nh_grp_res_idle_timer;
45 	unsigned long	nh_grp_res_unbalanced_timer;
46 	bool		nh_grp_res_has_num_buckets;
47 	bool		nh_grp_res_has_idle_timer;
48 	bool		nh_grp_res_has_unbalanced_timer;
49 
50 	bool		nh_hw_stats;
51 
52 	struct nlattr	*nh_encap;
53 	u16		nh_encap_type;
54 
55 	u32		nlflags;
56 	struct nl_info	nlinfo;
57 };
58 
59 struct nh_info {
60 	struct hlist_node	dev_hash;    /* entry on netns devhash */
61 	struct nexthop		*nh_parent;
62 
63 	u8			family;
64 	bool			reject_nh;
65 	bool			fdb_nh;
66 
67 	union {
68 		struct fib_nh_common	fib_nhc;
69 		struct fib_nh		fib_nh;
70 		struct fib6_nh		fib6_nh;
71 	};
72 };
73 
74 struct nh_res_bucket {
75 	struct nh_grp_entry __rcu *nh_entry;
76 	atomic_long_t		used_time;
77 	unsigned long		migrated_time;
78 	bool			occupied;
79 	u8			nh_flags;
80 };
81 
82 struct nh_res_table {
83 	struct net		*net;
84 	u32			nhg_id;
85 	struct delayed_work	upkeep_dw;
86 
87 	/* List of NHGEs that have too few buckets ("uw" for underweight).
88 	 * Reclaimed buckets will be given to entries in this list.
89 	 */
90 	struct list_head	uw_nh_entries;
91 	unsigned long		unbalanced_since;
92 
93 	u32			idle_timer;
94 	u32			unbalanced_timer;
95 
96 	u16			num_nh_buckets;
97 	struct nh_res_bucket	nh_buckets[] __counted_by(num_nh_buckets);
98 };
99 
100 struct nh_grp_entry_stats {
101 	u64_stats_t packets;
102 	struct u64_stats_sync syncp;
103 };
104 
105 struct nh_grp_entry {
106 	struct nexthop	*nh;
107 	struct nh_grp_entry_stats __percpu	*stats;
108 	u16		weight;
109 
110 	union {
111 		struct {
112 			atomic_t	upper_bound;
113 		} hthr;
114 		struct {
115 			/* Member on uw_nh_entries. */
116 			struct list_head	uw_nh_entry;
117 
118 			u16			count_buckets;
119 			u16			wants_buckets;
120 		} res;
121 	};
122 
123 	struct list_head nh_list;
124 	struct nexthop	*nh_parent;  /* nexthop of group with this entry */
125 	u64		packets_hw;
126 };
127 
128 struct nh_group {
129 	struct nh_group		*spare; /* spare group for removals */
130 	u16			num_nh;
131 	bool			is_multipath;
132 	bool			hash_threshold;
133 	bool			resilient;
134 	bool			fdb_nh;
135 	bool			has_v4;
136 	bool			hw_stats;
137 
138 	struct nh_res_table __rcu *res_table;
139 	struct nh_grp_entry	nh_entries[] __counted_by(num_nh);
140 };
141 
142 struct nexthop {
143 	struct rb_node		rb_node;    /* entry on netns rbtree */
144 	struct list_head	fi_list;    /* v4 entries using nh */
145 	struct list_head	f6i_list;   /* v6 entries using nh */
146 	struct list_head        fdb_list;   /* fdb entries using this nh */
147 	struct list_head	grp_list;   /* nh group entries using this nh */
148 	struct net		*net;
149 
150 	u32			id;
151 
152 	u8			protocol;   /* app managing this nh */
153 	u8			nh_flags;
154 	bool			is_group;
155 
156 	refcount_t		refcnt;
157 	struct rcu_head		rcu;
158 
159 	union {
160 		struct nh_info	__rcu *nh_info;
161 		struct nh_group __rcu *nh_grp;
162 	};
163 };
164 
165 enum nexthop_event_type {
166 	NEXTHOP_EVENT_DEL,
167 	NEXTHOP_EVENT_REPLACE,
168 	NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE,
169 	NEXTHOP_EVENT_BUCKET_REPLACE,
170 	NEXTHOP_EVENT_HW_STATS_REPORT_DELTA,
171 };
172 
173 enum nh_notifier_info_type {
174 	NH_NOTIFIER_INFO_TYPE_SINGLE,
175 	NH_NOTIFIER_INFO_TYPE_GRP,
176 	NH_NOTIFIER_INFO_TYPE_RES_TABLE,
177 	NH_NOTIFIER_INFO_TYPE_RES_BUCKET,
178 	NH_NOTIFIER_INFO_TYPE_GRP_HW_STATS,
179 };
180 
181 struct nh_notifier_single_info {
182 	struct net_device *dev;
183 	u8 gw_family;
184 	union {
185 		__be32 ipv4;
186 		struct in6_addr ipv6;
187 	};
188 	u32 id;
189 	u8 is_reject:1,
190 	   is_fdb:1,
191 	   has_encap:1;
192 };
193 
194 struct nh_notifier_grp_entry_info {
195 	u16 weight;
196 	struct nh_notifier_single_info nh;
197 };
198 
199 struct nh_notifier_grp_info {
200 	u16 num_nh;
201 	bool is_fdb;
202 	bool hw_stats;
203 	struct nh_notifier_grp_entry_info nh_entries[] __counted_by(num_nh);
204 };
205 
206 struct nh_notifier_res_bucket_info {
207 	u16 bucket_index;
208 	unsigned int idle_timer_ms;
209 	bool force;
210 	struct nh_notifier_single_info old_nh;
211 	struct nh_notifier_single_info new_nh;
212 };
213 
214 struct nh_notifier_res_table_info {
215 	u16 num_nh_buckets;
216 	bool hw_stats;
217 	struct nh_notifier_single_info nhs[] __counted_by(num_nh_buckets);
218 };
219 
220 struct nh_notifier_grp_hw_stats_entry_info {
221 	u32 id;
222 	u64 packets;
223 };
224 
225 struct nh_notifier_grp_hw_stats_info {
226 	u16 num_nh;
227 	bool hw_stats_used;
228 	struct nh_notifier_grp_hw_stats_entry_info stats[] __counted_by(num_nh);
229 };
230 
231 struct nh_notifier_info {
232 	struct net *net;
233 	struct netlink_ext_ack *extack;
234 	u32 id;
235 	enum nh_notifier_info_type type;
236 	union {
237 		struct nh_notifier_single_info *nh;
238 		struct nh_notifier_grp_info *nh_grp;
239 		struct nh_notifier_res_table_info *nh_res_table;
240 		struct nh_notifier_res_bucket_info *nh_res_bucket;
241 		struct nh_notifier_grp_hw_stats_info *nh_grp_hw_stats;
242 	};
243 };
244 
245 int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
246 			      struct netlink_ext_ack *extack);
247 int __unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
248 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
249 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
250 void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
251 				 bool offload, bool trap);
252 void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
253 				     unsigned long *activity);
254 void nh_grp_hw_stats_report_delta(struct nh_notifier_grp_hw_stats_info *info,
255 				  unsigned int nh_idx,
256 				  u64 delta_packets);
257 
258 /* caller is holding rcu or rtnl; no reference taken to nexthop */
259 struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
260 void nexthop_free_rcu(struct rcu_head *head);
261 
nexthop_get(struct nexthop * nh)262 static inline bool nexthop_get(struct nexthop *nh)
263 {
264 	return refcount_inc_not_zero(&nh->refcnt);
265 }
266 
nexthop_put(struct nexthop * nh)267 static inline void nexthop_put(struct nexthop *nh)
268 {
269 	if (refcount_dec_and_test(&nh->refcnt))
270 		call_rcu_hurry(&nh->rcu, nexthop_free_rcu);
271 }
272 
nexthop_cmp(const struct nexthop * nh1,const struct nexthop * nh2)273 static inline bool nexthop_cmp(const struct nexthop *nh1,
274 			       const struct nexthop *nh2)
275 {
276 	return nh1 == nh2;
277 }
278 
nexthop_is_fdb(const struct nexthop * nh)279 static inline bool nexthop_is_fdb(const struct nexthop *nh)
280 {
281 	if (nh->is_group) {
282 		const struct nh_group *nh_grp;
283 
284 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
285 		return nh_grp->fdb_nh;
286 	} else {
287 		const struct nh_info *nhi;
288 
289 		nhi = rcu_dereference_rtnl(nh->nh_info);
290 		return nhi->fdb_nh;
291 	}
292 }
293 
nexthop_has_v4(const struct nexthop * nh)294 static inline bool nexthop_has_v4(const struct nexthop *nh)
295 {
296 	if (nh->is_group) {
297 		struct nh_group *nh_grp;
298 
299 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
300 		return nh_grp->has_v4;
301 	}
302 	return false;
303 }
304 
nexthop_is_multipath(const struct nexthop * nh)305 static inline bool nexthop_is_multipath(const struct nexthop *nh)
306 {
307 	if (nh->is_group) {
308 		struct nh_group *nh_grp;
309 
310 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
311 		return nh_grp->is_multipath;
312 	}
313 	return false;
314 }
315 
316 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
317 
nexthop_num_path(const struct nexthop * nh)318 static inline unsigned int nexthop_num_path(const struct nexthop *nh)
319 {
320 	unsigned int rc = 1;
321 
322 	if (nh->is_group) {
323 		struct nh_group *nh_grp;
324 
325 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
326 		if (nh_grp->is_multipath)
327 			rc = nh_grp->num_nh;
328 	}
329 
330 	return rc;
331 }
332 
333 static inline
nexthop_mpath_select(const struct nh_group * nhg,int nhsel)334 struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
335 {
336 	/* for_nexthops macros in fib_semantics.c grabs a pointer to
337 	 * the nexthop before checking nhsel
338 	 */
339 	if (nhsel >= nhg->num_nh)
340 		return NULL;
341 
342 	return nhg->nh_entries[nhsel].nh;
343 }
344 
345 static inline
nexthop_mpath_fill_node(struct sk_buff * skb,struct nexthop * nh,u8 rt_family)346 int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
347 			    u8 rt_family)
348 {
349 	struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
350 	int i;
351 
352 	for (i = 0; i < nhg->num_nh; i++) {
353 		struct nexthop *nhe = nhg->nh_entries[i].nh;
354 		struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
355 		struct fib_nh_common *nhc = &nhi->fib_nhc;
356 		int weight = nhg->nh_entries[i].weight;
357 
358 		if (fib_add_nexthop(skb, nhc, weight, rt_family, 0) < 0)
359 			return -EMSGSIZE;
360 	}
361 
362 	return 0;
363 }
364 
365 /* called with rcu lock */
nexthop_is_blackhole(const struct nexthop * nh)366 static inline bool nexthop_is_blackhole(const struct nexthop *nh)
367 {
368 	const struct nh_info *nhi;
369 
370 	if (nh->is_group) {
371 		struct nh_group *nh_grp;
372 
373 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
374 		if (nh_grp->num_nh > 1)
375 			return false;
376 
377 		nh = nh_grp->nh_entries[0].nh;
378 	}
379 
380 	nhi = rcu_dereference_rtnl(nh->nh_info);
381 	return nhi->reject_nh;
382 }
383 
nexthop_path_fib_result(struct fib_result * res,int hash)384 static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
385 {
386 	struct nh_info *nhi;
387 	struct nexthop *nh;
388 
389 	nh = nexthop_select_path(res->fi->nh, hash);
390 	nhi = rcu_dereference(nh->nh_info);
391 	res->nhc = &nhi->fib_nhc;
392 }
393 
394 /* called with rcu read lock or rtnl held */
395 static inline
nexthop_fib_nhc(struct nexthop * nh,int nhsel)396 struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
397 {
398 	struct nh_info *nhi;
399 
400 	BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
401 	BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
402 
403 	if (nh->is_group) {
404 		struct nh_group *nh_grp;
405 
406 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
407 		if (nh_grp->is_multipath) {
408 			nh = nexthop_mpath_select(nh_grp, nhsel);
409 			if (!nh)
410 				return NULL;
411 		}
412 	}
413 
414 	nhi = rcu_dereference_rtnl(nh->nh_info);
415 	return &nhi->fib_nhc;
416 }
417 
418 /* called from fib_table_lookup with rcu_lock */
419 static inline
nexthop_get_nhc_lookup(const struct nexthop * nh,int fib_flags,const struct flowi4 * flp,int * nhsel)420 struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh,
421 					     int fib_flags,
422 					     const struct flowi4 *flp,
423 					     int *nhsel)
424 {
425 	struct nh_info *nhi;
426 
427 	if (nh->is_group) {
428 		struct nh_group *nhg = rcu_dereference(nh->nh_grp);
429 		int i;
430 
431 		for (i = 0; i < nhg->num_nh; i++) {
432 			struct nexthop *nhe = nhg->nh_entries[i].nh;
433 
434 			nhi = rcu_dereference(nhe->nh_info);
435 			if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
436 				*nhsel = i;
437 				return &nhi->fib_nhc;
438 			}
439 		}
440 	} else {
441 		nhi = rcu_dereference(nh->nh_info);
442 		if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
443 			*nhsel = 0;
444 			return &nhi->fib_nhc;
445 		}
446 	}
447 
448 	return NULL;
449 }
450 
nexthop_uses_dev(const struct nexthop * nh,const struct net_device * dev)451 static inline bool nexthop_uses_dev(const struct nexthop *nh,
452 				    const struct net_device *dev)
453 {
454 	struct nh_info *nhi;
455 
456 	if (nh->is_group) {
457 		struct nh_group *nhg = rcu_dereference(nh->nh_grp);
458 		int i;
459 
460 		for (i = 0; i < nhg->num_nh; i++) {
461 			struct nexthop *nhe = nhg->nh_entries[i].nh;
462 
463 			nhi = rcu_dereference(nhe->nh_info);
464 			if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
465 				return true;
466 		}
467 	} else {
468 		nhi = rcu_dereference(nh->nh_info);
469 		if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
470 			return true;
471 	}
472 
473 	return false;
474 }
475 
fib_info_num_path(const struct fib_info * fi)476 static inline unsigned int fib_info_num_path(const struct fib_info *fi)
477 {
478 	if (unlikely(fi->nh))
479 		return nexthop_num_path(fi->nh);
480 
481 	return fi->fib_nhs;
482 }
483 
484 int fib_check_nexthop(struct nexthop *nh, u8 scope,
485 		      struct netlink_ext_ack *extack);
486 
fib_info_nhc(struct fib_info * fi,int nhsel)487 static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
488 {
489 	if (unlikely(fi->nh))
490 		return nexthop_fib_nhc(fi->nh, nhsel);
491 
492 	return &fi->fib_nh[nhsel].nh_common;
493 }
494 
495 /* only used when fib_nh is built into fib_info */
fib_info_nh(struct fib_info * fi,int nhsel)496 static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
497 {
498 	WARN_ON(fi->nh);
499 
500 	return &fi->fib_nh[nhsel];
501 }
502 
503 /*
504  * IPv6 variants
505  */
506 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
507 		       struct netlink_ext_ack *extack);
508 
509 /* Caller should either hold rcu_read_lock(), or RTNL. */
nexthop_fib6_nh(struct nexthop * nh)510 static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
511 {
512 	struct nh_info *nhi;
513 
514 	if (nh->is_group) {
515 		struct nh_group *nh_grp;
516 
517 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
518 		nh = nexthop_mpath_select(nh_grp, 0);
519 		if (!nh)
520 			return NULL;
521 	}
522 
523 	nhi = rcu_dereference_rtnl(nh->nh_info);
524 	if (nhi->family == AF_INET6)
525 		return &nhi->fib6_nh;
526 
527 	return NULL;
528 }
529 
fib6_info_nh_dev(struct fib6_info * f6i)530 static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
531 {
532 	struct fib6_nh *fib6_nh;
533 
534 	fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
535 	return fib6_nh->fib_nh_dev;
536 }
537 
nexthop_path_fib6_result(struct fib6_result * res,int hash)538 static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
539 {
540 	struct nexthop *nh = res->f6i->nh;
541 	struct nh_info *nhi;
542 
543 	nh = nexthop_select_path(nh, hash);
544 
545 	nhi = rcu_dereference_rtnl(nh->nh_info);
546 	if (nhi->reject_nh) {
547 		res->fib6_type = RTN_BLACKHOLE;
548 		res->fib6_flags |= RTF_REJECT;
549 		res->nh = nexthop_fib6_nh(nh);
550 	} else {
551 		res->nh = &nhi->fib6_nh;
552 	}
553 }
554 
555 int nexthop_for_each_fib6_nh(struct nexthop *nh,
556 			     int (*cb)(struct fib6_nh *nh, void *arg),
557 			     void *arg);
558 
nexthop_get_family(struct nexthop * nh)559 static inline int nexthop_get_family(struct nexthop *nh)
560 {
561 	struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
562 
563 	return nhi->family;
564 }
565 
566 static inline
nexthop_fdb_nhc(struct nexthop * nh)567 struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh)
568 {
569 	struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
570 
571 	return &nhi->fib_nhc;
572 }
573 
nexthop_path_fdb_result(struct nexthop * nh,int hash)574 static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh,
575 							    int hash)
576 {
577 	struct nh_info *nhi;
578 	struct nexthop *nhp;
579 
580 	nhp = nexthop_select_path(nh, hash);
581 	if (unlikely(!nhp))
582 		return NULL;
583 	nhi = rcu_dereference(nhp->nh_info);
584 	return &nhi->fib_nhc;
585 }
586 #endif
587